Grapevine water use in Central New Mexico.

NMSU viticulture has initiated a study to determine how much water grapevines growing in central New Mexico require to produce a 3-6 ton/acre crop of wine grapes destined for sparkling wine production. 

                An exploratory, observational study was initiated in 2018 at a  ~30 acre commercial vineyard at the Pueblo of Santa Ana, Sandoval County, NM (just north of Bernalillo, NM, east of I-25), to measure and calculate the seasonal water requirement of three Vitis vinifera winegrape varieties: Chardonnay, Pinot Meunier and Pinot Noir, grown for sparkling wine production. Although it is widely established that wine grape growers can more efficiently manage their irrigation systems and the amount of water applied to grapes once the grapevine’s water requirement for a desired fruit composition and yield level is known (Williams 2001), this has not been accomplished within New Mexico.

Figure 1. Average soil moisture (%) at 6 depths in three blocks at Santa Ana Vineyard , NM, from October 31, 2018 to October 26 , 2019.

In figure 1 above, notice that the soil moisture (%) in the Pinot Meunier block was substantially greater across all depths except 1000 mm. This block is located at the lowest elevation compared to the other two and the alluvial soil, with an associated greater water holding capacity may have played a role in this trend. We will repeat the study next year with more replications to determine if this is the case. 

Close up of HH2 unit being used to capture soil moisture readings at 100, 200, 300, 400, 600, and 1000 mm  under the trellis in the vine row at Santa Ana Pueblo Vineyard, Sandoval County, NM.

Figure 2. Stem water potential of three varieties during the growing season 2019. The dotted line indicates level of stem water potential (-1.0 MPa) that water stress is likely to occur

Scholander pressure chamber used to determine level of water status of grapevines during the growing season. 

Wikepedia: pressure bomb_Check out the explanation of a pressure chamber and how it is used to determine water potential ( or how water stessed ) a plant maybe at any given time.